Abstract

To solve the large size faultiness of Oryza sativa recombinant human serum albumin nanoparticle (OsrHSA NP), the structural discrepancies between OsrHSA and plasma-derived human serum albumin (pdHSA) were analyzed deeply in this research. It demonstrated that there were some subtle structural discrepancies located in subdomain IA and IIA between OsrHSA and pdHSA, which included peptide backbone, disulphide bridge and some amino acids. Firstly, the structural discrepancies were investigated through literature comparison, it inferred that the structural discrepancies resulted from the fatty acid (FA) binding to OsrHSA at site 2 of subdomain IA and IIA. To form a cavity for accommodation of FA molecule in OsrHSA, the peptide backbone structure of subdomain IA and IIA would change, accompanied by the conformational transition of disulphide bridges and side chain structure change of some amino acids in subdomain IA and IIA. These alterations induced the exposure of tryptophan (Trp) and tyrosine (Tyr) residues in subdomain IA and IIA and the decrease of net negative charges of molecular surface. The former would promote more OsrHSA molecules aggregate, and the latter would weaken the electrostatic repulsion. As a result, the size of OsrHSA NP was more extensive than that of pdHSA NP (175.84 ± 15.63 nm vs. 31.67 ± 1.31 nm) when the concentration of Dimethyl Sulphoxide (DMSO) was 30% (v/v). In this study, the experimental scheme of OsrHSA NP preparation was improved. There were two changes in the enhanced preparation scheme: pH 8.2 PBS buffer and 63% DMSO. It indicated that the improved OsrHSA NP carrier was comparable to the pdHSA NP carrier. The size and drug loading of paclitaxel-loaded improved OsrHSA NP were 53.57 ± 3.63 nm and 7.25 ± 0.46% (w/w), and those of docetaxel-loaded improved OsrHSA NP were 44.75 ± 2.26 nm and 8.43 ± 0.74% (w/w). Moreover, both NPs exhibited good stability for 168 h at 7.4 pH values. It is established that the improved OsrHSA NP is comparable to the pdHSA NP as a taxane delivery system.

中文翻译：

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研究水稻重组体和血浆来源的人血清白蛋白之间的细微结构差异，以设计作为紫杉烷递送系统的新型纳米颗粒

摘要

为了解决Oryza sativa重组人血清白蛋白纳米颗粒（OsrHSA NP）尺寸较大的缺陷，本研究深入分析了OsrHSA与血浆源人血清白蛋白（pdHSA）之间的结构差异。结果表明，OsrHSA 和 pdHSA 的 IA 和 IIA 子域存在一些细微的结构差异，包括肽骨架、二硫桥和一些氨基酸。首先，通过文献比较研究了结构差异，推测结构差异是由于脂肪酸（FA）在亚结构域IA和IIA的第2位点与OsrHSA结合造成的。为了在OsrHSA中形成容纳FA分子的空腔，子结构域IA和IIA的肽主链结构会发生变化，同时伴随着二硫键的构象转变以及子结构域IA和IIA中一些氨基酸的侧链结构的变化。这些改变导致亚结构域IA和IIA中色氨酸（Trp）和酪氨酸（Tyr）残基的暴露以及分子表面净负电荷的减少。前者会促进更多的OsrHSA分子聚集，后者会减弱静电斥力。结果，当二甲基亚硫酸盐 (DMSO) 浓度为 30% (v/v) 时，OsrHSA NP 的尺寸比 pdHSA NP 的尺寸更大（175.84 ± 15.63 nm vs. 31.67 ± 1.31 nm）。本研究改进了OsrHSA NP制备的实验方案。增强制备方案有两个变化：pH 8.2 PBS 缓冲液和63% DMSO。这表明改进的OsrHSA NP载体与pdHSA NP载体相当。载有紫杉醇的改进型 OsrHSA NP 的尺寸和载药量分别为 53.57 ± 3.63 nm 和 7.25 ± 0.46% (w/w)，载有多西他赛的改进型 OsrHSA NP 的尺寸和载药量分别为 44.75 ± 2.26 nm 和 8.43 ± 0.74% (w/w)。 w）。此外，两种 NP 在 7.4 pH 值下在 168 小时内均表现出良好的稳定性。经证实，作为紫杉烷递送系统，改进的 OsrHSA NP 与 pdHSA NP 相当。